Twin fluke anchor having improved shank-crown contact

ABSTRACT

A twin fluke anchor in which the shank is limited in angular displacement by engagement with the leading edge of the crown side wall, thus allowing increased crown-shank engagement forces.

United States Patent [191 Hungerford Nov. 13, 1973 TWIN FLUKE ANCHORHAVING IMPROVED SHANK-CROWN CONTACT [75] inventor: Daniel ComstockHungerford, North Palm Beach, Fla.

[73] Assignee: Brunswick Corporation, Skokie, Ill.

[22] Filed: Sept. 7, 1971 [21] Appl. No.: 178,232

[52] US. Cl 114/208 R [51] Int. Cl B63b 21/44 [58] Field of Search114/206, 207, 208 R [56] References Cited UNITED STATES PATENTS3,332,387 7/1967 Winslow 114/208 R 3,382,835 5/1968 McGuire 114/208 RPrimary Examiner-Milton Buchler Assistant Examiner-Galen L. BarefootAttorneyBarry L. Haley [5 7] ABSTRACT A twin fluke anchor in which theshank is limited in angular displacement by engagement with the leadingedge of the crown side wall, thus allowing increased crown-shankengagement forces.

6 Claims, 8 Drawing Figures PATENTEI] NOV 13 I975 SHEET 1 UF 2 pE/OEr497 PATENIEDHOV 13 ms 3.771.486

sum 2 BF 2 BY 73 m 3 JQTTOE/VEY TWIN FLUKE ANCHOR HAVING IMPROVEDSHANK-CROWN CONTACT BACKGROUND OF THE INVENTION This invention relatesgenerally to the field of anchors, and more specifically to a twin flukeanchor having an improved shank angular displacement stop.

With a twin fluke anchor, in order to achieve proper fluke penetrationand holding in the sea bottom for maximum force, a critical angle ofabout 32 between the plane of the flukes and the shank must beestablished and maintained. In the past this angle was formed when thelateral edge of the shank contacted the crown plate leading edge. Thecontact forces acted to separate the crown plate from theperpendicularly coupled crown walls and to produce a shear force in theplane of the crown plate. The result if too large a force is presentedis the destruction of the crown or distortion of the crown plate suchthat the optimum maximum fluke-shank angle has been exceeded thus makingthe anchor unuseable. These problems prohibit or reduce the use oflightweight. metals such as aluminum because of their lower shear forcelimits.

Applicants invention replaces the shank-crown plate shear force with acrown side wall leading edge compression force capable of withstandingmuch greater shank-crown contact forces for a given size and weightanchor.

BRIEF DESCRIPTION OF THE INVENTION A twin fluke anchor having a crown, apair of flukes joined to said crown, a shank pivotally coupled to saidcrown, the crown having a pair of oppositely disposed crown plates, apair of parallel side walls joined to said crown plates, the side wallsbeing oriented substantially parallel to the plane of movement of theshank, and a contact means coupled to said shank engageable with theleading edge of at least one crown side wall to limit the angulardisplacement of said shank substantially equally on each side of a planecontaining the flukes. The contact means or the leading edge of thecrown side wall is contoured so that at engagement the shank is limitedto a predetermined angular value with respect to said fluke plane. Theshank is prevented from exerting large forces on the crown plates.

It is an object of this invention to provide a twin fluke anchor havingincreased holding capabilities.

It is another object of this invention to provide an anchor withimproved crown-shank contact.

And yet another object of this invention is to provide an anchor havinga crown-shank engagement with increased structural integrity fordefining maximum shank angular movement.

In accordance with these and other objects which will be apparenthereinafter, the instant invention will now be described with particularreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a showing of the prior art.

FIG. 2a is a side elevation view of applicants crown and shank assembly.

FIG. 2b is a side elevation view showing an alternate embodiment with adifferent shank stop angle.

FIG. 20 is a sie elevation view showing another alternative embodimentwith a different shank stop angle.

FIG. 3 is an end-on elevation of applicants invention.

FIG. 4 is a diagram of the angular relationships on applicants stopsurface.

FIG. 5 is a perspective view of an anchor in accordance with applicantsinvention.

FIG. 6 is a side elevation view of an alternate embodiment of applicantsinvention.

PREFERRED EMBODIMENT OF THE INVENTION Referring now to the drawings, andin particular to FIG. 1, an anchor crown 10 is shown as prior art. Thecrown 10 has a pair of diverging crown plates 12 and 16 which arecoupled to opposite edges of crown side plates 14. Shank pivot shaft 20is coupled at each end to one of the side plates 14 and the shank 18 ispivotally joined to the shaft 20. Line AA represents the fluke planeaxis which is fixed with respect to the crown (the flukes being rigidlycoupled to the crown). The flukes lie in the fluke plane and aresymetrical about the fluke plane axis AA. The prior art shows shank 18moveable about each side of the fluke. plane axis AA the optimum maximumamount of 32. The shank is stopped at its outer limits on each side ofthe axis AA by either crown plate 12 or 16. The lateral edge of shank 18directly contacts the leading edge of crown plate 12 or plate 16, andquite often the force from shank 18 on the plate is sufficient toseparate the plate 12 from the side walls 14 or distort the leading edgeof the plate 12 such that a new, undesirable angle between the shank l8and the axis AA would be created. The plate arrangement shown isunsatisfactory for use with light weight materials or large shankforces.

Applicants device for overcoming these problems is shown in FIG. 2a.Applicants crown 22 has diverging crown plates 24 and 28 coupled toopposite edges of parallel crown side plates 26 and 34. A shank pivotshaft 32 is coupled between side plates 26 and 34, and shank 30 ispivotally coupled near one end about the shaft 32. The shank 30 ismoveable from a center position 1 which lies in fluke plane axis BB tomaximum angular positions 2 and 3 above and below the axis 8-8respectively. A pair of shank stops 36 and 38 having angularly pointingsurfaces are disposed on each side of shank 30 and are thick enough andproject out from the shank surface so that at the maximum angularpositions 2 and 3, the shank stops 36 and 38 contact the verticalleading edges of crown side walls 26 and 34 respectively. The stoppingmeans 36 and 38 move in a circular are as the shank 3 is moved about thepivot shaft 32 (FIG. 2a). The stopping means project outward from theshank (FIG. 3) and are positioned radially from the pivot shaft 32 adistance so that their end faces will engage the side wall leading edges26 and 34 when the center of the shank is 32 on either side of flukeplane axis BB. Both stopping means are coupled to the shank by a longscrew 42. Any conventional holding means would be satisfactory.

The contact portion of the shank stopping means may be of anygeometrical shape, but as shown in the preferred embodiment, fiatsurface engagement with flat surface will distribute the force on thecrown wall leading edge more evenly. In FIG. 2a the leading edges of thecrown side walls are perpendicular with respect to the fluke plane. InFIGS. 2b and 2c, the leading edges are obliquely and acutely angledrespectively with the fluke plane. Thus in each example, the angle ofthe contact surface of stopping means 36 with respect to the shanklongitudinal axis is selected so that engagement with the crown sidewall leading edge surface will be between flat surfaces. This angle isestablished (FIG. 4) generally after having chosen the maximum shankfluke plane angle to be utilized (e.g. 32), by determining the anglebetween the leading edge of the crown side wall and the fluke plane(shank neutral position) (90) and subtracting the maximum shank-flukeplane angle (32) which results in the required angle (58) between thecontacting surface of the stopping means and the shank longitudinal axis(same as the fluke plane axis when the shank is in the neutralposition). Because the shank pivot shaft is behind the crown side wallleading edge, the distance of the stopping means from the shank pivotshaft will vary as a function of the angle between the crown wallleading edge and the fluke plane. In FIG. 4, line DD represents thecrown wall leading edge surface, line C-C the longitudinal axis of theshank and line EE the contacting surface of the stopping means 36. Withan obliquely angled crown wall leading edge as in FIG. 2b, thecontacting surface of stopping means 36 is perpendicular to theshanklongitudinal axis (line BB when shank is in the neutral position), whilein FIG. 20 both the crown wall leading edge and the contacting surfaceof stopping means 36 are acutely angled with respect to line 8-8. InFIGS. 2b and 20, positions 1, 2, and 3 represent the shank neutral andmaximum positions respectively with the stopping means 36 engaged withthe leading edges of crown wall side 26 on each side of the fluke planeaxis B-B.

FIG. shows a twin fluke anchor constructed according to applicantsinvention. Stopping means 42 are disposed on each side of shank 30 andengage crown side walls 26 and 34 to limit shank movement on either sideof line B-B which lies in' the plane of flukes 38 and 40 to the optimummaximum angle of 32. The flukes 38 and 40 are coupled to stock 52 andthe crown side walls 26 and 34 in any standard way.

FIG. 6 shows an alternate embodiment with crown side wall 46 coupled attop and bottom to crown plates 44 and 48. The leading edge of side wall46 is contoured in a hill-and-dale fashion so as to receive circularprojecting member 52 which projects away from the shank 50 sides. Thepositions 1, 2, and 3 of shank 50 show the neutral (fluke plane axis),upper maximum and lower maximum respectively. At maximum shank angles,the projecting member is engaged in a circular projecting member isprovided on each side of shank 50 (not shown) and likewise both sidewall leading edges are contoured the same. The projecting members 54 actto stop and limit the angular movement of shank 50 at predeterminedoptimum angles on either side of the fluke plane axis B-B.

Although the shank stopping means or projecting means has been shown tobe a wedge or circular projection from the shank side, any shank flangeor projecting element that overlaps the leading edge and engages thecrown wall leading edge so that the crown plates are not engaged wouldbe satisfactory to practice applicants invention.

The instant invention has been shown and described herein in what isconsidered to be the most practical and preferred embodiment. It isrecognized, however, that departures may be made therefrom within thescope of the invention and that obvious modifications will occur to aperson skilled in the art.

What I claim is:

l. A twin fluke anchor comprising:

a stock;

a pair of flukes coupled at their edges to said stock;

a crown having a pair'of oppositely disposed side walls and a pair ofcrown plates oppositely disposed joining the top edges and bottom edgesof said side walls;

shank pivot means connected to said crown side walls;

a shank pivotally connected at one end to said pivot means; and

shank stopping means for stopping shank angular pivotal motion securedto said shank and engageable with the leading edges of said side wallsat predetermined angular positions of said shank on either side of aplane containing'said flukes.

2. An anchor as in claim 1, wherein:

said stopping means is a wedge shaped block having two surfacesangularly disposed facing said leading edge of said crown side walls,with each surface flushly engageably with the leading edge surface atpredetermined maximumangular positions of said shank and fluke plane.

3. An anchor as in claim 1, wherein:

said stopping means is a shaped element projecting from said shanklateral surface; and

said crown side wall leading edge is contoured to engage flushly withsaid shaped projecting element.

4. A twin fluke anchor comprising:

a stock;

a crown having a pair of oppositely disposed side walls and a pair ofcrown plates oppositely disposed joining the top edges and the bottomedges of said side walls;

- shank pivot means connected to crown side walls;

a shank pivotally connected at one end to said pivot means; and

means connected to said shank for stopping the pivotal motion of saidshank, said stopping means engageable with the leading edges of saidside walls at a predetermined angular position of said shank on eitherside of a plane containing said flukes.

5. In a twin fluke anchor having a stock, a pair of flukes coupled alongtheir back edges to said stock, a crown coupled to said stock, and ashank pivotally coupled to saidcrown, the improvement comprising:

a shank stop for stopping shank angular pivotal motion connected to saidshank and engageable with at least one of the front planar faces of saidcrown side walls, said side walls substantially parallel to the plane ofpivotal movement of said shank, said shank stop engaging the frontplanar face of said side wall edges stopping the shank at apredetermined angle of pivotal movement relative to the plane of saidflukes.

6. A twin fluke anchor comprising:

a pivot rod connecting said flukes;

an elongated shank pivotally connected between said flukes to said pivotrod;

a crown housing connected to said pivot rod and extending about saidshank on all sides, said crown housing having a first side and a secondside substantially parallel to the plane of motion of said shank; and

a shank angular pivotal motion stopping means for stopping shank angularpivotal motion connected to said shank and engageable with the frontface of said first and said second housing sides to determine a maximumangle of movement of said shank on either side of said flukes.

1. A twin fluke anchor comprising: a stock; a pair of flukes coupled at their edges to said stock; a crown having a pair of oppositely disposed side walls and a pair of crown plates oppositely disposed joining the top edges and bottom edges of said side walls; shank pivot means connected to said crown side walls; a shank pivotally connected at one end to said pivot means; and shank stopping means for stopping shank angular pivotal motion secured to said shank and engageable with the leading edges of said side walls at predetermined angular positions of said shank on either side of a plane containing said flukes.
 2. An anchor as in claim 1, wherein: said stopping means is a wedge shaped block having two surfaces angularly disposed facing said leading edge of said crown side walls, with each surface flushly engageably with the leading edge surface at predetermined maximum angular positions of said shank and fluke plane.
 3. An anchor as in claim 1, wherein: said stopping means is a shaped element projecting from said shank lateral surface; and said crown side wAll leading edge is contoured to engage flushly with said shaped projecting element.
 4. A twin fluke anchor comprising: a stock; a crown having a pair of oppositely disposed side walls and a pair of crown plates oppositely disposed joining the top edges and the bottom edges of said side walls; shank pivot means connected to crown side walls; a shank pivotally connected at one end to said pivot means; and means connected to said shank for stopping the pivotal motion of said shank, said stopping means engageable with the leading edges of said side walls at a predetermined angular position of said shank on either side of a plane containing said flukes.
 5. In a twin fluke anchor having a stock, a pair of flukes coupled along their back edges to said stock, a crown coupled to said stock, and a shank pivotally coupled to said crown, the improvement comprising: a shank stop for stopping shank angular pivotal motion connected to said shank and engageable with at least one of the front planar faces of said crown side walls, said side walls substantially parallel to the plane of pivotal movement of said shank, said shank stop engaging the front planar face of said side wall edges stopping the shank at a predetermined angle of pivotal movement relative to the plane of said flukes.
 6. A twin fluke anchor comprising: two flat flukes; a pivot rod connecting said flukes; an elongated shank pivotally connected between said flukes to said pivot rod; a crown housing connected to said pivot rod and extending about said shank on all sides, said crown housing having a first side and a second side substantially parallel to the plane of motion of said shank; and a shank angular pivotal motion stopping means for stopping shank angular pivotal motion connected to said shank and engageable with the front face of said first and said second housing sides to determine a maximum angle of movement of said shank on either side of said flukes. 